SECT. I. General Remarks on the Nature and Origin of Winds, ib. 10. Whirlwinds of Sand XLI. On the Prester, or Water-Spout ii. Genuine Presters, or Water-Spouts ib. ii. Communication and Velocity of Electricity iii. Atmospherical Electricity XLIII. Electricity of Thunder and Lightning SECT. i. General History of this Interesting Discovery iii. Means of preventing Mischief from Lightning SECT. i. General Remarks on the Theory of Magnetism v. Parselia, or Mock.Sins, seen at Danzic 521 1. Pyramidal Appearance in the heaven, observed in 522 vii, Parkeria at Sudhary, Sufik 523 www. Two Mock-Suns and an Are of a Rainbow in- 524 ix. Beautiful Iridescent Arches in a Mist 526 1. Peculier Solar and Lunar Irises in South America 528 529 xis, Description of a Glory on Mount Realt, near the 530 XLIX. Of Sounds and Echoes 533 Sr. i. General Observations on the Nature of Sound, Whispering Domes, and Echoes ii. Extraordinary Whispering Places and Echoes ib. 546 547 t t THE GALLERY OF NATURE AND ART PART I. NATURE. BOOK II. GEOLOGY. [CONTINUED.] CHAP. XXXIV. ATMOSPHERICAL DEPARTMENT. We now advance to the atmospherical phænomena of the science of Geology, in the extensive sense in which we have em. ployed this term; and shall proceed to a brief survey of whatever is most curious or worthy of observation in the composition of the Atmosphere; the variation of Climate; the extremes of Heat and Cold; the existence of Electricity and electric Powers, as Thunder and Lightning, Aurora Borealis, Water-spouts; Falling-stars, and Ignes Fatui; Echoes, Wind, Hurricanes, and Storms; the origin of Mist, Dew, Sleet, Snow, Mirages, or Fata Morgana, Meteoric, Stones, and various other appearances connected with or dependent upon the preceding; and which collectively constitute the Science of Meteorology. VOL, IV. CHAP. XXXV. GENERAL NATURE OF THE ATMOSPHERE. THE atmosphere is that invisible elastic fald which surrounds the carta to an unknown height, and incloses it on all sides. It was thas denominated by the Greeks in consequence of the vavours which are continually mixing with it, or combined in it*. Ia contemplating the nature of the atmosphere there are two points of considerable importance to be attended to, respecting which therefore we shall offer a summary of the best established facts and opinions of the present day; and these are the materials that enter into its composition, and the changes to which it is liable. SECTION 1. Composition of the Atmosphere. NEITHER the properties nor the composition of the atmosphere seems to have occupied much of the attention of the ancients. Aristotle considered it as one of the four elements, situated be. tween the regions of water and fire, and mingled with two exhalations, the dry and moist; the first of which occasioned thunder, lightning, and wind; while the second produced rain, snow, and hail. The ancients, in general, seem to have considered the blue. colours of the sky as essential to the atmosphere; and several of their philosophers believed that it was the constituent principle of other bodies, or at least that air and other bodies are mutually convertible into each other. Thus Lucretius: Semper enim quodcunque fluit de rebus, id omne • From ärμ, a vapour, and epaïpa, a sphere, Lib. v. 274. |